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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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<SEC-DOCUMENT>0000716039-04-000010.txt : 20040102
<SEC-HEADER>0000716039-04-000010.hdr.sgml : 20040101
<ACCEPTANCE-DATETIME>20040102135256
ACCESSION NUMBER:		0000716039-04-000010
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20031231
FILED AS OF DATE:		20040102

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			WHITMAN MARLNA V N
		CENTRAL INDEX KEY:			0001190706

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-08483
		FILM NUMBER:		04500897

	MAIL ADDRESS:	
		STREET 1:		C/O PROCTER & GAMBLE CO
		STREET 2:		ONE PROCTER & GAMBLE PLAZA
		CITY:			CINCINNATI
		STATE:			OH
		ZIP:			4552025

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			UNOCAL CORP
		CENTRAL INDEX KEY:			0000716039
		STANDARD INDUSTRIAL CLASSIFICATION:	CRUDE PETROLEUM & NATURAL GAS [1311]
		IRS NUMBER:				953825062
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		2141 ROSECRANS AVE
		STREET 2:		STE 4000
		CITY:			EL SEGUNDO
		STATE:			CA
		ZIP:			90245
		BUSINESS PHONE:		3107267600

	MAIL ADDRESS:	
		STREET 1:		2141 ROSECRANS AVE
		STREET 2:		STE 4000
		CITY:			EL SEGUNDO
		STATE:			CA
		ZIP:			90245
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>f4forwhit.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2003-12-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000716039</issuerCik>
        <issuerName>UNOCAL CORP</issuerName>
        <issuerTradingSymbol>UCL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001190706</rptOwnerCik>
            <rptOwnerName>WHITMAN MARLNA V N</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>% UNOCAL CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>2141 ROSECRANS AVE, STE 4000</rptOwnerStreet2>
            <rptOwnerCity>EL SEGUNDO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90245</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock $1.00 Par Value</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2003-12-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>43.0162</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>32.7109</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>15104.5905</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>

        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock $1.00 Par Value</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2003-12-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F3"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>366.8502</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>32.7109</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>15471.4407</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>

    </nonDerivativeTable>


    <derivativeTable>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Common Stock has attached Preferred Stock Purchase Rights.
If and when the Rights become exercisable, the holders
would initially be entitled to purchase one one-hundredth
of a share of Series B Junior Participating Preferred stock
at a purchase price determined pursuant to the Rights
Agreement.</footnote>
        <footnote id="F2">Units credited for dividend equivalent on deferred
compensation under the 2001 Directors' Deferred
Compensation and Stock Award Plan.  Each unit is payable in
one share of Common Stock at the end of the deferral
periods.</footnote>
        <footnote id="F3">Deferred compensation under the 2001 Directors'
Deferred Compensation and Stock Award Plan.  Each unit is
payable in one share of Common Stock at the end of the
deferral periods.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Paul R. Moore, Attorney-In-Fact</signatureName>
        <signatureDate>2004-01-02</signatureDate>
    </ownerSignature>

</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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